In the past paper was printed with primarily water or oil based inks which were satisfactorily removed by conventional deinking procedures. In conventional deinking procedures, the paper is mechanically pulped and contacted with an aqueous medium containing a deinking chemical. The pulping and presence of the deinking chemical resulted in a separation of the ink from the pulp fibers and the dispersed ink is then separated from the pulp fibers by washing or flotation processes.
Today, increasing amounts of printed paper are generated from electrophotographic processes such as xerography and non-impact printing processes such as laser and ink-jet printing. Deinking processes capable of deinking these types of printed paper are very complex and are capital intensive. In addition, multiple steps are required for debris removal and actual ink removal. Generally, ink removal procedures involve washing, flotation, forward cleaning and high consistency dispersion to reach the level of speck removal and brightness required in the deinked pulp to create recyclable paper.
U.S. Pat. No. 4,561,933 to Wood, discloses a process for deinking xerographically printed wastepaper. Repulped printed wastepaper is treated with a deinking agent consisting of a mixture of alkanols and alcohol ethoxylates to produce a suspension of ink particles. The suspended ink particles are separated from the resulting pulp-medium by washing and flotation process steps. The deinking chemical and process in Wood, however, is limited to deinking only xerographic waste and utilizes multiple process steps to separate the ink.
To surmount these limitations, and as an alternative to conventional deinking procedures, the prior art has shown use of agglomeration deinking processes. Agglomeration chemicals consisting of polymeric systems and surfactant systems are employed to aid in the ink agglomeration process. In deinking paper through agglomeration the waste paper is repulped and then deinked through chemical treatment to provide a slurry of pulp and ink agglomerates. The ink agglomerates are removed from the pulp by sedimentation and separation. However, the polymeric and surfactant systems used in these agglomeration processes are specific to certain types of inks. See U.S. Pat. No. 4,820,379 to Darlington (polymeric system) and U.S. Pat. No. 5,141,598 to Richman et al. (surfactant system), in which the deinking compositions are specific for agglomeration of electrostatic inks, and U.S. Pat. No. 4,076,578 to Puddington et al. (polymeric system) in which the deinking chemical is specific for agglomeration of newspaper inks.
Therefore, known deinking processes are not entirely satisfactory in that the chemicals used are selective as to the type of ink. Also high concentrations of expensive chemicals are necessary to obtain effective deinking results. Such processes are cost inefficient.
Thus the present practice, employing known deinking processes and agglomeration chemicals, has problems in deinking a wide variety of impact and non-impact printed paper. The inventions and practice to date, deal with deinking chemicals having limitations to specific inks and deinking processes which require complex and expensive procedures to obtain recyclable grade paper.
There is a need in the art for deinking processes which cause agglomeration of all types of inks, both impact and nonimpact, for all grades of paper. This invention is directed to the provision of such processes which have wide range applications in creating recyclable grade paper. It would be appreciated that advantage over conventional deinking procedures would be obtained by providing an effective and efficient deinking method applicable to all types of printed paper.
Accordingly, it is a broad object of the invention to provide a deinking process utilizing a deinking composition for the agglomeration of all types of inks, both impact and nonimpact, from wood containing and wood free grades of paper.
A more specific object of the invention is to provide a deinking method which utilizes agglomeration deinking compositions comprising one or more nonionic surfactants and/or alkanols for the agglomeration of all types of inks, both impact and nonimpact, from wood containing and wood free grade of paper.
A further specific object of the invention is to provide deinking compositions comprising one or more C5 to C20 alcohol ethoxylates having an ethoxylate content sufficient to provide detergency or wetting.
Another more specific object of the invention is to provide deinking compositions comprising one or more C5 to C20 alkanols or a composition comprising a blend with the alcohol ethoxylates.
Another object of the invention is to provide a low cost agglomeration deinking process that effectively and efficiently removes ink without using a high concentration of expensive agglomeration chemicals.
A further specific object of the invention is to provide an agglomeration deinking method which is less complex than the prior art ink removal procedures.
Another object of the invention is to provide a recycled paper product made by the agglomeration deinking method of the invention from impact and/or nonimpact printed paper.
A further specific object of the invention is to provide an apparatus for deinking impact and/or nonimpact printed paper utilizing a repulping means, an agglomeration means, a separation means and a production means to produce recyclable grade paper.